Contribution to aroma potential of Andean blackberry (Rubus glaucus Benth.)

Abstract

Free and glycosidically bound volatiles of purees from Andean blackberry (Rubus Glaucus Benth.) fruit were determined. Free volatile compounds were extracted by two techniques: solvent extraction and Solid-Phase Micro-Extraction (SPME). The glycosidically bound volatiles were isolated using Solid Phase Extraction (SPE) technique. The analysis of free volatiles and enzymatically released aglycons were performed by GC-MS. Fifty five volatile compounds were identified and quantified from solvent extraction. The major class was the carboxylic acids (68.8%), dominated by palmitic acid (16.8%) and benzoic acid (15.0%). Alcohols were highly represented (23.4%), with 2-heptanol (10.6%) and terpinen-4-ol (5.7%) being prevalent compounds of this class. Using HS-SPME, among the seventy-one identified compounds, alcohols (47.3%) including 2-heptanol (17.9%) and terpinen-4-ol (20.0%), and esters (39.8%) with ethyl and methyl benzoate (33.9 and 3.8% respectively) were the two predominant classes. β-damascenone, a potent flavour compound was detected using SPME method. Fifty-three aglycons were identified, acids (57.4%), norisoprenoids (15.4%), terpenic alcohols (10.3%) and some aliphatic and shikimic alcohols (15.0%) predominated in the glycosidically bound fraction. Acetylenic precursors of β-damascenone were present at noticeable level in the glycosidic fraction.